Method to prepare compositions comprising yeast treated with electromagnetic energy

ABSTRACT

The present invention relates to pharmaceutical compositions and dietary supplement comprising yeast cells that can produce a healthful benefit in a subject inflicted with nasopharyngeal cancer. The biological compositions can be used to retard the growth of nasopharyngeal cancer cells and/or prolonging the time of survival of the subject. The invention also relates to methods for manufacturing the biological compositions.

1. FIELD OF THE INVENTION

The invention relates to oral compositions comprising yeast cells that can produce a healthful benefit in a subject inflicted with nasopharyngeal cancer. The invention also relates to methods for manufacturing the oral compositions and methods of use thereof.

2. BACKGROUND OF THE INVENTION

2.1 Nasopharyngeal Cancer

Nasopharyngeal cancer (NPC), although rare in North American, is the seventh and ninth leading cause of death for men and women, respectively, from Taiwan, southern China (in particular, Hong Kong and the province of Guangdong), and Southeast Asia. NPC comprises 18% to 25% of all cancers in these endemic areas while it represents only 0.2% of all malignancies in the United States (J. Cary, Moorhead, Md., 1994, “Nasopharyngeal cancer”). The most frequently suspected etiologic factors associated with the development of nasopharyngeal cancer are viral, genetic and environmental. Other risk factors include smoky surrounding, preserved food-rich diets such as salted and pickled fish, smoked meat, sausage or duck with high levels of salt, nitrite and/or N-nitrosamines, low intake of fresh vegetables and fruits, and cigarette smoking.

It is extremely difficult to diagnose NPC for several reasons. First, the symptoms are nonspecific at the early stages of the disease. Second, the tumor tends to spread submucosally and thus remains clinically unapparent even to direct inspection. Most importantly, the nasopharynx region is inaccessible to general examination and therefore, makes diagnosis difficult. The mean delay form the onset of the first symptom to diagnosis was reported to be six months (Skinner et al., 1990, Ear Nose Throat J. 69:237–252). Patients with NPC are most often present with a cervical mass from metastatic spread to a lymph node. Other possible presentations include ipsilateral serous otitis, hearing loss, nasal obstruction, frank epistaxis, purulent or bloody rhinorrhea, and facial neuropathy or facial nerve palsies.

A neck mass is consistently one of the most common presentations, and unfortunately, a sign of advanced disease. In fact, more than 50% of the patients when being detected of the cancer are in advance disease stages, and for this group of patients the 5 year survival figures are only around 50% after radiotherapy alone. Specifically, biopsy data reflects an extremely high rate of aberrant metastatic spread, which has been identified as the leading cause for death in NPC patients. Once the tumor begins to spread to the head and neck and to subcutaneous and cutaneous sites, the patients' average life span is down to about 4 months.

Studies show that 90% of nasopharyngeal cancer patients are infected with the Epstein-Barr virus (EBV), compared to less than 10% in the general public. Accordingly, Serologic markers for the Epstein-Barr virus (EBV) also plays a role in detection of the disease (Mutirangura, 2001, Ann NY Acad Sci. 945:59–67). DNA from EBV is found in nasopharyngeal tissues, and elevated titers of IgG and IgA antibodies are seen in all patients with nasopharyngeal cancer (Niedobitek et al., 1991, J Path. 165:17–24). Elevated titers have been used as a marker to screen populations in high-risk areas and as an indicator of the likelihood for relapse.

Using the World Health Organization classification system, NPC is histologically subclassified into types 1, 2 and 3. Under this scheme, type 1 carcinoma is the most differentiated and is also known as keratinizing squamous cell carcinoma, accounting for 25% of all NPC. Type 2 NPC, also referred to as non-keratinizing, is the least common, representing only 12% of NPC. WHO type 3 is also called undifferentiated carcinoma and accounts for 63% of NPC. Despite their histologic appearance, all of these tumors have been demonstrated by electron microscopy to be varieties of squamous cell carcinoma.

The staging of NPC is based on the revised criteria of TNM staging by the American Joint Committee for Cancer (AJCC) published in 1988. Staging is the process of describing the extent to which cancer has spread from the site of its origin. It is used to assess a patient's prognosis and to determine the choice of therapy. The stage of a cancer is determined by the size and location in the body of the primary tumor, and whether it has spread to other areas of the body. Staging involves using the letters T, N and M to assess tumors by the size of the primary tumor (T); the degree to which regional lymph nodes (N) are involved; and the absence or presence of distant metastases (M)—cancer that has spread from the original (primary) tumor to distant organs or distant lymph nodes. Each of these categories is further classified with a number 1 through 4 to give the total stage. Once the T, N and M are determined, a “stage” of I, II, III or IV is assigned. Stage I cancers are small, localized and usually curable. Stage II and III cancers typically are locally advanced and/or have spread to local lymph nodes. Stage IV cancers usually are metastatic (have spread to distant parts of the body) and generally are considered inoperable.

Radiotherapy is the mainstay of therapy for NPC due both to the inaccessibility of the tumor to surgery, and also to the surprising radiosensitivity of the lesion. However, the close proximity of the tumor to many vital structures makes NPC one of the most challenging tumors for the radiotherapist to treat. Although a wide variety of protocols is used, a standard recommended treatment regimen is 6500 to 7000 cGy delivered to the tumor by a linear accelerator by one anterior and two laterally opposed fields. Shielding of the eyes, tongue, brainstem, and spinal cord is essential. Small cancers of the nasopharynx are highly curable by radiation therapy, with survival rates of 80% to 90% (Ho, 1996, Int J Radiat Oncol Biol Phys. 35(3):463–469).

Surgery plays only a supportive role in the treatment of NPC because it is limited by the inaccessibility of the lesion and the difficulty in achieving resection of the tumor with clear margins in the face of the convoluted nasopharyngeal anatomy. In refractory cases, reirradiation techniques such as arc radiation or intracavitary implants would generally be considered preferable to surgery. Surgery for cervical lymphadenopathy is usually reserved for salvage following radiation therapy.

On the other hand, chemotherapy may be used as an adjunct to radiation therapy. The addition of chemotherapy may decrease the possibility of distant metastatic spread by eradicating micrometastases. In general, chemotherapy can achieve long-term survival rates of up to 15% to 20%, even in patients with recurrent or metastatic disease (Ali et al., 2000, Oncology 14(8):1223–30). Unfortunately, the high initial response rates to first line chemotherapy does not appear to translate into a survival benefit (Kohno and Kitahara, 2001, Gan To Kagaku Ryoho 28(4):448–53). Moreover, there are many undesirable side effects associated with chemotherapy such as temporary hair loss, mouth sores, anemia (decreased numbers of red blood cells that may cause fatigue, dizziness, and shortness of breath), leukopenia (decreased numbers of white blood cells that may lower resistance to infection), thrombocytopenia (decreased numbers of platelets that may lead to easy bleeding or bruising), and gastrointestinal symptoms like nausea, vomiting and diarrhea. Active chemotherapeutic agents include cyclosporin A, Taxol, Cisplatin, Carboplatin, Adriamycin, Doxil, Topotecan, Methotrexate, Bleomycin and Epirubicin.

The identification of active chemotherapeutic agents against cancers traditionally involved the use of various animal models of cancer. The mouse has been one of the most informative and productive experimental system for studying carcinogenesis (Sills et al., 2001, Toxicol Letters 120:187–198), cancer therapy (Malkinson, 2001, Lung Cancer 32(3):265–279; Hoffman R M., 1999, Invest New Drugs 17(4):343–359), and cancer chemoprevention (Yun, 1999, Annals NY Acad Sci. 889:157–192). Cancer research started with transplanted tumors in animals which provided reproducible and controllable materials for investigation. Pieces of primary animal tumors, cell suspensions made from these tumors, and immortal cell lines established from these tumor cells propagate when transplanted to animals of the same species.

To transplant human cancer to an animal and to prevent its destruction by rejection, the immune system of the animal are compromised. While originally accomplished by irradiation, thymectomy, and application of steroids to eliminate acquired immunity, nude mice that are athymic congenitally have been used as recipients of a variety of human tumors (Rygaard, 1983, in 13^(th) International Cancer Congress Part C, Biology of Cancer (2), pp 37–44, Alan R. Liss, Inc., NY; Fergusson and Smith, 1987, Thorax, 42:753–758). While the athymic nude mouse model provides useful models to study a large number of human tumors in vivo, it does not develop spontaneous metastases and are not suitable for all types of tumors. Next, the severe combined immunodeficient (SCID) mice is developed in which the acquired immune system is completely disabled by a genetic mutation. Human lung cancer was first used to demonstrate the successful engraftment of a human cancer in the SCID mouse model (Reddy S., 1987, Cancer Res. 47(9):2456–2460). Subsequently, the SCID mouse model have been shown to allow disseminated metastatic growths for a number of human tumors, particularly hematologic disorders and malignant melanoma (Mueller and Reisfeld, 1991, Cancer Metastasis Rev. 10(3):193–200; Bankert et al., 2001, Trends Immunol. 22:386–393). With the recent advent of transgenic technology, the mouse genome has become the primary mammalian genetic model for the study of cancer (Resor et al., 2001, Human Molec Genet. 10:669–675).

While surgery, chemotherapeutic agents and radiation are useful in the treatment of nasopharyngeal cancer, there is a continued need to find better treatment modalities and approaches to manage the disease that are more effective and less toxic, especially when clinical oncologists are giving increased attention to the quality of life of cancer patients. The present invention provides an alternative approach to cancer therapy and management of the disease by using an oral composition comprising yeasts.

2.2 Yeast-Based Compositions

Yeasts and components thereof have been developed to be used as dietary supplement or pharmaceuticals. However, none of the prior methods uses yeast cells which have been cultured in an electromagnetic field to produce a product that has an anti-cancer effect. The following are some examples of prior uses of yeast cells and components thereof:

U.S. Pat. No. 6,197,295 discloses a selenium-enriched dried yeast product which can be used as dietary supplement. The yeast strain Saccharomyces boulardii sequela PY 31 (ATCC 74366) is cultured in the presence of selenium salts and contains 300 to about 6,000 ppm intracellular selenium. Methods for reducing tumor cell growth by administration of the selenium yeast product in combination with chemotherapeutic agents is also disclosed.

U.S. Pat. No. 6,143,731 discloses a dietary additive containing whole β-glucans derived from yeast, which when administered to animals and humans, provide a source of fiber in the diet, a fecal bulking agent, a source of short chain fatty acids, reduce cholesterol and LDL, and raises HDL levels.

U.S. Pat. No. 5,504,079 discloses a method of stimulating an immune response in a subject utilizing modified yeast glucans which have enhanced immunobiologic activity. The modified glucans are prepared from the cell wall of Saccharomyces yeasts, and can be administered in a variety of routes including, for example, the oral, intravenous, subcutaneous, topical, and intranasal route.

U.S. Pat. No. 4,348,483 discloses a process for preparing a chromium yeast product which has a high intracellular chromium content. The process comprises allowing the yeast cells to absorb chromium under a controlled acidic pH and, thereafter inducing the yeast cells to grow by adding nutrients. The yeast cells are dried and used as a dietary supplement.

Citation of documents herein is not intended as an admission that any of the documents cited herein is pertinent prior art, or an admission that the cited documents are considered material to the patentability of the claims of the present application. All statements as to the date or representations as to the contents of these documents are based on the information available to the applicant and does not constitute any admission as to the correctness of the dates or contents of these documents.

3. SUMMARY OF THE INVENTION

The present invention relates to biological or oral compositions useful for subjects with nasopharyngeal cancer. In one embodiment, the present invention provides biological compositions comprising live yeast cells which are capable of producing a healthful benefit in subjects with nasopharyngeal cancer. In other embodiments, the invention provides methods of making the biological compositions, and methods of using the biological compositions.

In particular, the methods of the invention comprise culturing yeast cells in the presence of a series of electromagnetic fields such that the yeast cells becomes metabolically active. The electromagnetic fields used are each defined by one of five frequency ranges and a broad range of field strength. The starting yeast cells are commercially available and/or accessible to the public, such as but not limited to Saccharomyces. The methods for making the biological compositions of the invention further comprise conditioning the activated yeast cells in plant extracts and the gastric juice of animals, while in the presence of another series of electromagnetic fields.

The methods of manufacturing also comprise expanding the number of activated or activated and conditioned yeast cells in large scale cultures in the presence of yet another series of electromagnetic fields, performing quality control measures, and packaging. Pharmaceutical compositions of the invention comprises activated and conditioned yeast cells and one or more pharmaceutically acceptable excipients or carriers. Additional ingredients, such as vitamins and/or flavors may be added to the biological compositions to form the oral compositions of the invention. Such additional carriers and ingredients can improve the healthful benefits, pharmacological properties, and organoleptic characteristics of the oral compositions. During the manufacturing process, the activated or activated and conditioned yeast cells may be dried and stored for a period of time.

The biological or oral compositions of the invention are ingested by the subject or used as an additive to be incorporated into food to be consumed by the subject. Dietary supplement and nutritional compositions comprising activated and conditioned yeast cells are encompassed by the invention. Preferably, the subject is a human being.

In various embodiments, the biological or oral compositions of the invention are used to produce a healthful benefit in a subject with nasopharyngeal cancer or at high risk of developing nasopharyngeal cancer. In particular, the biological composition of the invention can retard the growth of nasopharyngeal cancer cells in an animal which received the composition orally. The composition can also be used to prolong the time of survival of an animal with nasopharyngeal cancer.

4. BRIEF DESCRIPTION OF FIGURES

FIG. 1 Activation and conditioning of yeast cells. 1 yeast cell culture; 2 container; 3 electromagnetic field source; 4 electrode.

FIG. 2 Large scale propagation of yeast cells. 5 first container; 6 second container; 7 third container; 8 yeast cell cultures; 9 electromagnetic field source.

5. DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to biological compositions that can produce a healthful benefit in a subject with nasopharyngeal cancer. The present invention provides methods for manufacturing the biological compositions as well as methods for using the biological compositions.

In one embodiment, the invention provides biological compositions that comprise yeasts. Unlike the traditional use of yeasts in the making of food, the yeast cells of the invention are not used as a source of enzymes that acts on the food ingredients. The yeasts are not a primary source of nutrients for the subject. Nor are yeast cells used as a carrier, such as metal salts. The yeast cells of the invention are live when administered orally or ingested along with food by a subject. Without being bound by any theory or mechanism, the inventor believes that the culture conditions activate and/or amplified the expression of a gene or a set of genes in the yeast cells such that the yeast cells becomes highly effective in stimulating the animal's immune system, including both specific and non-specific immunological reactions, the results of which are manifested as the overall healthful benefits observed in the treated subject. The healthful benefits provided by using the biological compositions are demonstrated in animal models of human nasopharyngeal cancer which show inhibition of tumor growth and prolonged survival time of animals with the disease.

In another embodiment, the invention provides methods for making the yeast cells in the biological compositions. The starting materials are normal yeast cells which can be readily obtained commercially or from public microorganism deposits. The methods of the invention comprise a set of culture conditions that can be applied reproducibly to activate the yeast cells. The key feature of the culture conditions used in the methods of the invention is a series of alternating electromagnetic fields of defined frequency ranges and field strengths which are applied to the growing yeast cell culture. The method further comprises the step of conditioning the activated live yeast cells to the acidic environment of the stomach of the subject. The electromagnetic fields used in these methods can be created reproducibly at various scales, thus enabling even the large scale manufacturing of the biological compositions of the invention. By careful control of the culturing conditions, normal yeast cells can be activated routinely and reproducibly to become yeast cells of the invention.

In yet another embodiment, the invention provides methods for manufacturing an oral composition comprising activated and conditioned yeasts of the invention, and additional ingredients, including but not limited to pharmaceutically acceptable carriers or excipients, vitamins, herbs (including traditional Chinese medicine products), herbal extracts, minerals, amino acids, flavoring agents, coloring agents, and/or preservatives.

In yet another embodiment, the biological compositions can be added to food which will be consumed by the subject. As known to those skilled in the relevant art, many methods may be used to mix the biological or oral compositions of the invention with food while the yeast cells remain viable. In a particular embodiment, the culture broth comprising live yeast cells of the present invention are added directly to food just prior to consumption. Dried powders of the yeasts can also be reconstituted and added directly to food just prior to consumption.

In various embodiments, the oral compositions of the invention can be consumed directly by a subject or be fed directly to a subject. For example, the subject may drink the culture broth or a fraction thereof that comprises live activated and conditioned yeast cells. Oral compositions comprising dried yeast cells can also be given as a solid dosage form to the subject.

Although it is not necessary, the biological or oral compositions of the invention can be used in conjunction or in rotation with other types of treatment modalities such as but not limited to surgery, chemotherapeutic agents, and radiation. Since the biological compositions of the invention are administered orally, the assistance of health professionals in administration of the composition is generally not essential.

Described below in Section 5.1 are the yeast cells of the invention and methods of their preparation. Section 5.2 describes the use of the biological compositions of the invention in a subject suffering from nasopharyngeal cancer. The examples in Sections 6 to 9 demonstrate the therapeutic benefits of an oral composition of the invention. The activated and conditioned yeast cells in the oral composition are characterized by their ability to (i) suppress the growth of cancer cells in an animal model of human nasopharyngeal cancer, or (ii) prolong the survival of animals with transplanted cancer cells in a model of human nasopharyngeal cancer, as compared to yeast cells which have not been activated and conditioned.

5.1 Preparation of the Yeast Cell Cultures

The yeast cells of the biological composition are produced by culturing a plurality of yeast cells in an appropriate culture medium in the presence of an alternating electromagnetic field over a period of time. The method comprises a first step of activating the yeast cells and a second step of conditioning the activated yeast cells. The activation process comprises culturing yeast cells in the presence of at least two, three, four or five electromagnetic fields of specific frequencies and field strength. The conditioning process comprises further culturing of the activated yeast cells in a medium comprising plant extracts and extracts from the stomach of an animal, in the presence of at least one electromagnetic field. The activated and conditioned yeast cells can be stored as dried cells after drying the cells under appropriate conditions. The dried activated and conditioned yeast cells can be used later in large scale culturing processes for manufacturing the biological compositions of the invention. The various culturing processes of the invention can be performed either as a batch process or a continuous process.

5.1.1 Yeasts

In various embodiments, yeasts of the genera of Saccharomyces, Candida, Crebrothecium, Geotrichum, Hansenula, Kloeckera, Lipomyces, Pichia, Rhodosporidium, Rhodotorula, Torulopsis, Trichosporon, and Wickerhamia can be used in the invention. Generally, fungi used for food manufacturing are preferred.

Non-limiting examples of yeast strains include Saccharomyces sp., AS2.311; Schizosaccharomyces pombe Linder, AS2.214, AS2.248, AS2.249, AS2.255, AS2.257, AS2.259, AS2.260, AS2.274, AS2.994, AS2.1043, AS2.1149, AS2.1178, IFFI 1056; Saccharomyces sake Yabe, ACCC2045; Saccharomyces uvarum Beijer, IFFI 1023, IFFI 1032, IFFI 1036, IFFI 1044, IFFI 1072, IFFI 1205, IFFI 1207; Saccharomyces rouxii Boutroux, AS2.178, AS2.180, AS2.370, AS2.371; Saccharomyces cerevisiae Hansen Var. ellipsoideus, ACCC2043, AS2.2, AS2.3, AS2.8, AS2.53, AS2.163, AS2.168, AS2.483, AS2.541, AS2.559, AS2.606, AS2.607, AS2.611, AS2.612; Saccharomyces carlsbergensis Hansen, AS2.116, AS2.162, AS2.189, AS2.200, AS2.216, AS2.265, AS2.377, AS2.417, AS2.420, AS2.440, AS2.441, AS2.443, AS2.444, AS2.459, AS2.595, AS2.605, AS2.638, AS2.742, AS2.745, AS2.748, AS2.1042; Rhodotorula aurantiaca (Saito)Ladder; AS2.102, AS2.107, AS2.278, AS2.499, AS2.694, AS2.703, AS2.704 and AS2.1146; Saccharomyces cerevisiae Hansen, ACCC2034, ACCC2035, ACCC2036, ACCC2037, ACCC2038, ACCC2039, ACCC2040, ACCC2041, ACCC2042, AS2.1, AS2.4, AS2.11, AS2.14, AS2.16, AS2.56, AS2.69, AS2.70, AS2.93, AS2.98, AS2.101, AS2.109, AS2.110, AS2.112, AS2.139, AS2.173, AS2.182, AS2.196, AS2.242, AS2.336, AS2.346, AS2.369, AS2.374, AS2.375, AS2.379, AS2.380, AS2.382, AS2.393, AS2.395, AS2.396, AS2.397, AS2.398, AS2.399, AS2.400, AS2.406, AS2.408, AS2.409, AS2.413, AS2.414, AS2.415, AS2.416, AS2.422, AS2.423, AS2.430, AS2.431, AS2.432, AS2.451, AS2.452, AS2.453, AS2.458, AS2.460, AS2.463, AS2.467, AS2.486, AS2.501, AS2.502, AS2.503, AS2.504, AS2.516, AS2.535, AS2.536, AS2.558, AS2.560, AS2.561, AS2.562, AS2.576, AS2.593, AS2.594, AS2.614, AS2.620, AS2.628, AS2.631, AS2.666, AS2.982, AS2.1190, AS2.1364, AS2.1396, IFFI 1001, IFFI 1002, IFFI 1005, IFFI 1006, IFFI 1008, IFFI 1009, IFFI 1010, IFFI 1012, IFFI 1021, IFFI 1027, IFFI 1037, IFFI 1042, IFFI 1045, IFFI 1048, IFFI 1049, IFFI 1050, IFFI 1052, IFFI 1059, IFFI 1060, IFFI 1062, IFFI 1202, IFFI 1203, IFFI 1209, IFFI 1210, IFFI 1211, IFFI 1212, IFFI 1213, IFFI 1215, IFFI 1221, IFFI 1224, IFFI 1247, IFFI 1248, IFFI 1251, IFFI 1270, IFFI 1277, IFFI 1289, IFFI 1290, IFFI 1291, IFFI 1292, IFFI 1293, IFFI 1297, IFFI 1300, IFFI 1301, IFFI 1302, IFFI 1307, IFFI 1308, IFFI 1309, IFFI 1310, IFFI 1311, IFFI 1331, IFFI 1335, IFFI 1336, IFFI 1337, IFFI 1338, IFFI 1339, IFFI 1340, IFFI 1345, IFFI 1348, IFFI 1396, IFFI 1397, IFFI 1399, IFFI 1441 and IFFI 1443. Preferred yeast strains include but are not limited to S. cerevisiae AS2.501, AS2.502, AS2.503, AS2.504, AS2.535, AS2.558, AS2.560, AS2.561 and AS2.562.

Generally, yeast strains useful for the invention can be obtained from private or public laboratory cultures, or publicly accessible culture deposits, such as the American Type Culture Collection, 10801 University Boulevard, Manassas, Va. 20110-2209 and the China General Microbiological Culture Collection Center (CGMCC), China Committee for Culture Collection of Microorganisms, Institute of Microbiology, Chinese Academy of Sciences, Haidian, P.O. Box 2714, Beijing, 100080, China.

Non-limiting examples of using yeast cells of the invention with Saccharomyces carlsbergensis Hansen strain AS2.116 are provided in Sections 6 to 9 herein below. The yeast cells of the invention do not comprise an enhanced level of selenium or chromium relative to that found in naturally occurring yeast cells. In certain embodiments, the biological compositions do not comprise cells of Saccharomyces boulardii (for example, ATCC Accession No. 74366) or cells of a particular strain of Saccharomyces cerevisiae (strain Hansen CBS 5926) that is also commonly referred to as Saccharomyces boulardii.

Although it is preferred, the preparation of the yeast cells of the invention is not limited to starting with a pure strain of yeast. The yeast cells in the biological compositions may be produced by culturing a mixture of yeast cells of different species or strains. The constituents of a mixture of yeast cells can be determined by standard yeast identification techniques well known in the art.

In various embodiments of the invention, standard techniques for handling, transferring and storing yeasts are used. Although it is not necessary, sterile conditions or clean environments are highly desirable when carrying out the manufacturing processes of the invention, especially when the biological compositions are for human consumption. The manufacturing process can be adapted to meet regulatory guidelines on product safety and quality control by standard practice known in the art.

5.1.2 Electromagnetic Fields

As used herein, the terms “alternating electromagnetic field”, “electromagnetic field” or “EM field” are synonymous. An electromagnetic field useful in the invention can be generated by various means well known in the art. A schematic illustration of exemplary setups are depicted respectively in FIG. 1. An electromagnetic field of a desired frequency and a desired field strength is generated by an electromagnetic wave source (3) which comprises one or more signal generators that are capable of generating electromagnetic waves, preferably sinusoidal waves, and preferably in the frequency range of 1,500 to 15,000 MHz and most preferably 9,900 to 12,800 MHz. Such signal generators are well known in the art. Signal generators capable of generating signal with a narrower frequency range can also be used. If desirable, a signal amplifier can also be used to increase the output signal, and thus the strength of the EM field.

The electromagnetic field can be applied to the culture by a variety of means including placing the yeast cells in close proximity to a signal emitter connected to a source of electromagnetic waves. The signal generator is connected to the signal emitter by cables such as coaxial cables that can transmit signals up to greater than or equal to 30 GHz. Typically, the yeast cells are placed in a container which is made of material that is not an electric conductor, such as but not limited to plastic, resin, glass, and ceramic.

In one embodiment, the electromagnetic field is applied by signal emitters in the form of electrodes (4) that are submerged in a culture of yeast cells (1). In a preferred embodiment, one of the electrodes is a metal plate which is placed on the bottom of a non-conducting container (2), and the other electrode comprises a plurality of wires or tubes so configured inside the container such that the energy of the electromagnetic field can be evenly distributed in the culture. The electrodes are preferably made of copper. For an upright culture vessel, the tips of the wires or tubes are placed within 3 to 30 cm from the bottom of the vessel (i.e., approximately 2% to 10% of the height of the vessel from the bottom). Table 1 provides exemplary set up for culturing the yeast cells of the invention.

TABLE 1 height of culture medium in distance electrodes are range for distance of the non-conducting placed from the bottom the electrodes from the container (cm) of the container (cm) bottom (cm) 15 to 20 3 3 to 5 20 to 30 5 5 to 7 30 to 50 7  7 to 10 50 to 70 10 10 to 15  70 to 100 15 15 to 20 100 to 150 20 20 to 30 150 to 200 30 25 to 30

The number of electrodes used depends on both the volume of the culture and the diameter of the electrode. For example, for a culture having a volume of 10 liter or less, two or three electrodes having a diameter of between 0.5 to 2.0 mm can be used. For a culture volume of 10 to 100 liter of culture, the electrodes can have a diameter of 3.0 to 5.0 mm. For a culture volume of 100 to 1,000 liter, the electrodes can have a diameter of 6.0 to 15.0 mm. For a culture having a volume greater than 1,000 liter, the electrodes can have a diameter of between 20.0 to 25.0 mm.

5.1.3 Activation of Yeast Cells

According to the invention, the method for producing activated yeast cells of the invention comprises culturing yeast cells in the presence of at least two, three, four or five alternating electromagnetic (EM) fields.

The culture process can be initiated by inoculating 1,000 ml of medium with an inoculum of a selected yeast strain (such as one of those described in Section 5.1.1) such that the starting cell density of the culture is greater than about 10⁵ cells per ml. For example, Saccharomyces carlsbergensis Hansen strain AS2.116 can be used. The starting culture can be used to seed larger scale culture. The culture is maintained initially at 28° C. to 32° C. for 22 to 30 hours prior to exposure to the EM field(s), typically at 30° C. for 28 hours.

The culturing process may preferably be conducted under conditions in which the concentration of dissolved oxygen is between 0.025 to 0.08 mol/m³, preferably 0.04 mol/m³. The oxygen level can be controlled by any conventional means known in the art, including but not limited to stirring and/or bubbling.

The culture is most preferably carried out in a liquid medium which contains sources of nutrients assimilable by the yeast cells. Table 2 provides an exemplary medium for culturing the yeast cells of the invention.

TABLE 2 Medium Composition Quantity Sucrose or glucose 20 g Vitamin B₆ 40 μg Vitamin B₁₂ 40 μg Vitamin H 70 μg Fetal calf serum 25 ml KH₂PO₄ 0.20 g MgSO₄.7H₂O 0.25 g NaCl 0.30 g CaSO₄.2H₂O 0.20 g CaCO₃.5H₂O 4.0 g Peptone 2.5 g Autoclaved water 1,000 ml

The culturing medium is heated to 45° C. and cooled before adding the vitamin B₆, vitamin B₁₂, vitamin H, and fetal calf serum.

In general, carbohydrates such as sugars, for example, sucrose, glucose, fructose, dextrose, maltose, xylose, and the like and starches, can be used either alone or in combination as sources of assimilable carbon in the culture medium. The exact quantity of the carbohydrate source or sources utilized in the medium depends in part upon the other ingredients of the medium but, in general, the amount of carbohydrate usually varies between about 0.1% and 5% by weight of the medium and is preferably between about 0.2% and 2%. These carbon sources can be used individually, or several such carbon sources may be combined in the medium. Among the inorganic salts which can be incorporated in the culture media are the customary salts capable of yielding sodium, calcium, phosphate, sulfate, carbonate, and like ions. Non-limiting examples of nutrient inorganic salts are KH₂PO₄, (NH₄)₂HPO₄, CaCO₃, MgSO₄, NaCl, and CaSO₄.

It should be noted that the composition of the media provided in Table 2 is not intended to be limiting. The process can be scaled up or down according to needs. Various modifications of the culture medium may be made by those skilled in the art, in view of practical and economic considerations, such as the scale of culture and local supply of media components.

In certain embodiments, a series of at least two, three, four or five EM fields are applied to the culture of yeast cells, each having a different frequency within a stated range, and a different field strength within a stated range. The EM fields can be applied in any order and by any means known in the art, such as the apparatus described in Section 5.1.2. Although any of the following two, three or four EM fields can be applied, preferably, all five EM fields are applied.

For the first EM field, the frequency is in the range of 9,961 to 9,970 MHz and the field strength is in the range of 250 to 270 mV/cm. The yeast culture is exposed to this first EM field at 30±2° C. for about 22 hours.

For the second EM field, the frequency is in the range of 10,951 to 10,960 MHz and the field strength is in the range of 250 to 270 mV/cm. The yeast culture is exposed to this second EM field at 30±2° C. for about 10 hours.

For the third EM field, the frequency is in the range of 12,091 to 12,100 MHz and the field strength is in the range of 250 to 270 mV/cm. The yeast culture is exposed to this third EM field at 30±2° C. for about 24 hours.

For the fourth EM field, the frequency is in the range of 12,441 to 12,450 MHz and the field strength is in the range of 240 to 270 mV/cm. The yeast culture is exposed to this fourth EM field at 30±2° C. for about 10 hours.

For the fifth EM field, the frequency is in the range of 12,751 to 12,760 MHz and the field strength is in the range of 270 to 290 mV/cm. The yeast culture is exposed to this fifth EM field at 30±2° C. for about 24 hours.

In less preferred embodiments, the yeast cells can be cultured by exposure to two, three or four of the above-mentioned EM fields in a different order. The yeast cells can remain in the same container and use the same set of electromagnetic wave generator and emitters when switching from one EM field to another EM field.

The cell density of the culture at the end of the activation process is typically greater than about 10⁶ to 10⁹ cells per ml (estimated by hematocytometer). The activated yeast cells may be recovered from the culture by various methods known in the art, and stored at a temperature below about 0° C. to 4° C. The activated yeast cells recovered from the liquid culture may be dried and stored in powder form. Preferably, the powder form of the yeast cells comprises greater than about 10⁷ to 10¹⁰ yeast cells per gram.

5.1.4 Conditioning of Yeast Cells

According to the invention, performance of the activated yeast cells can be optimized by culturing the activated yeast cells in the presence of an extract from the stomach (e.g., the gastric juice) of an animal with physiology similar to the subject to which the biological composition will be administered. The inclusion of this additional conditioning process allows the activated yeast cells to adapt to and endure the acidic environment of the subject's stomach. The method for conditioning activated yeast cells of the invention comprises culturing yeast cells in such materials in the presence of at least one EM field.

The culture process can be initiated by inoculating 1,000 ml of a conditioning medium with about 10 gram of dried activated yeasts containing about 10¹⁰ cells per gram (as prepared by the methods described in Section 5.1.3). An equivalent number of yeast cells in culture, preferably greater than 10⁶ to 10⁹ cells per ml, more preferably at 10⁸ cells per ml, can also be used as an inoculum. The conditioning medium comprises per 1,000 ml about 700 ml of gastric juice of an animal and about 300 ml of wild hawthorn juice. The process can be scaled up or down according to needs.

The gastric juice of an animal can be obtained from the stomach content of a freshly slaughtered animal. Although not essential, the animal is preferably kept under a clean environment, and fed a standard diet, preferably germ-free. For example, the content of the stomach of a 120-day old pig is mixed with 2,000 ml of distilled water, and allowed to settle without stirring for 6 hours. The clear liquid above is collected for use as the gastric juice used in the conditioning process. The gastric juice of a pig can be used to condition yeast cells for use in a variety of mammals, including humans. Other methods that can be used to collect the gastric juice include centrifugation or filtration of the mixture to remove debris and/or microorganisms. The gastric juice so obtained can be stored at 4° C. Preferably, the collection procedures and storage are carried out under sterile conditions.

The wild hawthorn juice is an extract of wild hawthorn fruits prepared by slicing the fruits and drying the slices in air, preferably to less than 8% moisture (commercial dryer can be used if necessary), crushing the dried fruits to less than 20 mesh, and mixing 1,500 ml of water per 500 gram of the crushed wild hawthorn. The mixture is then allowed to settle without stirring for 6 hours, and the clear liquid above is collected for use as the wild hawthorn juice used in the conditioning process. Other methods that can be used to collect the hawthorn juice include centrifugation or filtration of the mixture. Preferably, the collection procedures and storage are carried out under sterile conditions.

The activated yeast cells are conditioned by culturing in at least one of the following two EM fields which can be applied by the apparatus described in Section 5.1.2 or any means known in the art:

The first EM field has a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 260 to 300 mV/cm. The temperature is maintained at 28° C. to 32° C., and typically at 30° C. The yeast culture is exposed to this first EM field for about 12 hours.

The second EM field has a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 290 to 310 mV/cm. The temperature is maintained at 28° C. to 32° C., and typically at 30° C. The yeast culture is exposed to this second EM field for about 36 hours.

In a preferred embodiment, the activated yeast cells are conditioned by culturing in both of the above-mentioned EM fields. In less preferred embodiments, the yeast cells are conditioned in the two different EM fields in a different order. In other embodiments, a series of EM fields having field characteristics within the ranges stated above can be applied to condition the yeast cells. The yeast cells can remain in the same container and use the same set of electromagnetic wave generator and emitters when switching from one EM field to another EM field.

The cell density of the culture at the end of the activation process is typically greater than about 10⁷ to 10¹⁰ cells per ml (estimated by hematocytometer). The activated and conditioned yeast cells may be recovered from the culture by various methods known in the art, and stored at a temperature below about 0° C. to 4° C.

The activated and conditioned yeast cells can be used directly in a biological composition or used as a starter culture for large scale manufacturing. The activated and conditioned yeast cells recovered from the liquid culture may be dried and stored in powder form. Preferably, the powder form of the activated and conditioned yeast cells comprises greater than about 10⁸ to 10¹¹ yeast cells per gram.

5.1.5 Large Scale Manufacturing

The present invention also encompasses methods of manufacturing of the biological compositions of the invention at a large scale. The activated and conditioned yeast cells as prepared by Sections 5.1.3 and 5.1.4 are propagated on a large scale to make the biological compositions of the invention. The method comprises culturing the yeast cells in the presence of one or more EM fields for a period of time, diluting the growing yeast cells with fresh medium, and repeating the process. The method can be carried out as a batch process or a continuous process.

In one preferred embodiment, a set of three containers (5, 6, 7) each comprising a set of electrodes for generating an electromagnetic field as described in Section 5.1.2 are set up each with 1,000 liters of a culture medium. See FIG. 2. The culture medium comprises nutrients assimilable by the yeast cells as shown in Table 3.

TABLE 3 Material Quantity Wild hawthorn juice 300 liters Jujube juice 300 liters Wu wei zi juice 300 liters Soybean juice 100 liters

The wild hawthorn juice is an extract of fresh wild hawthorn fruits prepared by washing the fruits clean, drying the fruits in air or using a commercial dryer to less than 8% moisture, crushing the dried fruits to less than 20 mesh, and mixing the crushed wild hawthorn with water at a ratio of 400 liters of water per 100 kg of crushed fruits. The mixture is then stirred continuously for 12 hours while the temperature is maintained at 28° C. to 30° C. The mixture is then centrifuged at 1,000 rpm to collect the supernatant which is used as described above. Preferably, the procedures are carried out under sterile conditions.

The jujube juice is an extract of fresh jujube fruits prepared by washing the fruits clean, drying the fruits to less than 8% moisture, crushing the dried fruits to less than 20 mesh, and mixing the crushed jujube with water at a ratio of 400 liters of water per 100 kg of crushed fruits. The mixture is then stirred continuously for 12 hours while the temperature is maintained at 28° C. to 30° C. The mixture is then centrifuged at 1,000 rpm to collect the supernatant which is used as described above. Preferably, the procedures are carried out under sterile conditions.

The wu wei zi juice is an extract of fresh berries of Schisandra chinensis plant prepared by washing the berries, drying the fruits to less than 8% moisture, crushing the dried berries to less than 20 mesh, and mixing the crushed berries with water at a ratio of 400 liters of water per 100 kg of crushed berries. The mixture is then stirred continuously for 12 hours while the temperature is maintained at 28° C. to 30° C. The mixture is then centrifuged at 1,000 rpm to collect the supernatant which is used as described above. Preferably, the procedures are carried out under sterile conditions.

The soybean juice is prepared by washing the soybeans, drying the soybeans to less than 8% moisture, crushing the soybeans to less than 20 mesh, and mixing the crushed soybeans with water. For 30 kg of soybeans, 130 liters of water is used. The mixture is then stirred continuously for 12 hours while the temperature is maintained at 28° C. to 30° C. The mixture is then centrifuged at 1,000 rpm to collect the supernatant which is used as described above. Preferably, the procedures are carried out under sterile conditions.

The first container is inoculated with activated or activated and conditioned yeast cells as prepared by the methods of Sections 5.1.4 and 5.1.5. About 1,000 gram of dried yeast powder are added to 1,000 liter of culture medium. Each gram of the dried yeast powder comprises about 10¹⁰ yeast cells. Instead of dried yeast cells, an equivalent number of yeast cells in a liquid medium can also be used, preferably greater than about 10⁶ to 10⁹ cells per ml, more preferably about 10⁷ cells per ml.

The yeast cells in the first container (5) are then subjected to a series of two EM fields. For the first EM field, which can be applied by the apparatus described in Section 5.1.2, the frequency is in the range of 12,441 to 12,450 MHz and the field strength is in the range of 310 to 330 mV/cm. The yeast culture is exposed to this first EM field for about 10 hours. The yeast cells are then subjected to a second EM field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 310 to 330 mV/cm. The yeast culture is exposed to this second EM field for about 12 hours. The yeast cells from the first container are then transferred to the second container which contains about 1,000 liter of the culture medium. In effect, the first yeast culture is diluted by about 50% with fresh culture medium.

In the second container (6), the yeast cells are again subjected to a series of two EM fields. The frequencies used in the second container are similar to those used in the first container but the field strengths are marginally lower. The first EM field has a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 240 to 255 mV/cm. The yeast culture is exposed to this EM field for about 10 hours. The yeast cells are then subjected to a second EM field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 330 to 350 mV/cm. The yeast culture is exposed to this second EM field for about 12 hours. The yeast cells from the second container are then transferred to the third container which contains yet another 1,000 liter of the culture medium. Again, the second yeast culture is diluted by about 50% with fresh culture medium.

In the third container (7), the yeast cells are again subjected to a series of two EM fields. The frequencies used in the third container are similar to those used in the first and second container but the field strengths are lower. The first EM field has a frequency in the range of 12,441 to 12,450 MHz and field strength in the range of 215 to 235 mV/cm. The yeast culture is exposed to this EM field for about 12 hours. The yeast cells are then subjected to a second EM field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 240 to 260 mV/cm. The yeast culture is exposed to this EM field for about 24 hours.

The yeast cell culture resulting from the end of this stage can be used directly as an oral composition of the invention, or used to form other compositions encompassed by the invention.

The cell density of the culture at the end of the large scale manufacturing process is typically greater than about 10⁸ to 10¹⁰ cells per ml (estimated by hematocytometer). The concentration of yeast cells in the medium can be concentrated or diluted accordingly. In certain embodiments, the concentration of yeast cells in the medium is in the range of 10³ to 10¹⁰ cells per ml. In less preferred embodiments, the concentration of yeast cells in the medium is in the range of 103 to 10⁶ cells per ml. In more preferred embodiments, the concentration of yeast cells in the medium is greater than 10⁶ to 10¹⁰ cells per ml. In most preferred embodiments, the concentration of yeast cells in the medium is in the range of 10⁶ to 5×10⁸ cells per ml.

Other ingredients that enhance the healthful benefits, pharmacological properties and/or organoleptic characteristics of the composition can be added to the yeast cell culture. To maintain viability and freshness of the composition, it is preferred that the various downstream and packaging process be carried out below room temperature, and preferably at 0° C. to 4° C. In one embodiment, the yeast cell culture can be packaged in liquid containers.

In another embodiment, the activated and conditioned yeast cells can be dried as follows. The yeast cell culture is first centrifuged under 75 to 100 g for 10 to 20 minutes to remove the supernatant. The residue which may contain up to 85% moisture is dried in a first dryer at a temperature not exceeding 60±2° C. for a period of 5 minutes so that yeast cells quickly became dormant. The yeast cells were then sent to a second dryer and dried at a temperature not exceeding 65±2° C. for a period of about 8 minutes to further remove at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 98%, or at least 99% of water. For example, the yeast cells may be dried to remove at least 88% of water so the dried yeast cells may contain up to 12% moisture.

After cooling to room temperature, the dried yeast cells can be packaged by standard pharmaceutical methods in various solid dosage form, each containing a predetermined amount of the dried material. In a preferred embodiment, the dried material comprises about 10⁵ to 10¹¹ cells per gram. In a more preferred embodiment, the dried material comprises about 10⁸ to 5×10¹⁰ cells per gram. In a most preferred embodiment, the dried material comprises about 5×10⁸ cells per gram.

In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers.

5.1.6 Preferred Embodiments

In one preferred embodiment, the invention provides a method for preparing a biological composition comprising activated and conditioned yeast cells, said method comprising in any order the steps of:

-   -   (a) culturing the yeast cells in a first electromagnetic field         having a frequency at 9,963 MHz and a field strength of 246         mV/cm;     -   (b) culturing the yeast cells in a second electromagnetic field         having a frequency at 10,956 MHz and a field strength of 250         mV/cm;     -   (c) culturing the yeast cells in a third electromagnetic field         having a frequency at 12,098 MHz and a field strength of 263         mV/cm;     -   (d) culturing the yeast cells in a fourth electromagnetic field         having a frequency at 12,446 MHz and a field strength of 244         mV/cm; and     -   (e) culturing the yeast cells in a fifth electromagnetic field         having a frequency at 12,757 MHz and a field strength of 276         mV/cm;         and after the last of the first five steps, the following steps         in any order:     -   (f) culturing the yeast cells in a liquid medium comprising wild         hawthorn juice and gastric juice of a mammal in a sixth         electromagnetic field having a frequency at 12,446 MHz and a         field strength of 275 mV/cm; and     -   (g) culturing the yeast cells in a liquid medium comprising wild         hawthorn juice and gastric juice of a mammal in a seventh         electromagnetic field having a frequency at 12,757 MHz and a         field strength of 303 mV/cm.

The activated and conditioned yeast cells obtained at the conclusion of this method is encompassed by the invention. Preferably, the yeast cells are Saccharomyces carlsbergensis Hansen strain AS2.116. These yeast cells can be used in the following method of further expanding number of activated and conditioned yeast cells.

In another preferred embodiment, the invention provides a method of mass producing a biological composition comprising activated and conditioned yeast cells, said method comprising culturing the activated and conditioned yeast cells prepared by the preferred embodiment described above in this section, in a medium comprising wild hawthorn juice, jujube juice, wu wei zi juice, and soybean juice, and in the presence of one or more series of electromagnetic fields. Each series of EM fields comprises two EM fields in the order stated:

-   -   (h) an eighth electromagnetic field or series of electromagnetic         fields having a frequency at 12,446 MHz and a field strength in         the range of 215 to 330 mV/cm, preferably at three fields         strengths, e.g., in the order of 312 mV/cm, 250 mV/cm, and 220         mV/cm; and     -   (i) a ninth electromagnetic field or series of electromagnetic         fields having a frequency at 12,757 MHz and a field strength in         the range of 240 to 350 mV/cm, preferably at three fields         strengths, e.g., in the order of 327 mV/cm, 343 mV/cm, and 251         mV/cm.

The series may be repeated several times, such as three times, each time using a slightly lower field strength.

5.2 Methods of Uses

5.2.1 Uses In Subjects with Nasopharyngeal Cancer

The present invention further provides methods of use of the biological compositions of the invention. In one embodiment, the biological composition is used as a medicament for treatment of nasopharyngeal cancer. In another embodiment, the biological composition is used as a dietary supplement, health food, or health drink. The methods comprise administering an effective amount of the biological composition to a subject in need. The biological composition may be administered orally, in liquid or solid form, or enterally through a feeding tube. As used herein, the term “an effective amount” means an amount sufficient to provide a therapeutic or healthful benefit in the context of nasopharyngeal cancer.

According to the invention, the biological composition can produce a healthful benefit in a subject suffering from nasopharyngeal cancer. Preferably, the subject is a human being. The subject in need is one who is diagnosed with nasopharyngeal cancer, with or without metastasis, at any stage of the disease (e.g., TX, T0, Tis, T1, T2, T3, T4, NX, N0, N1, MX, M0 and M1). As used herein, the term “nasopharyngeal cancer” includes but is not limited to squamous cell carcinoma, nonkeratinizing carcinomas, undifferentiated carcinomas and keratinizing carcinoma.

The subject may be a nasopharyngeal cancer patient who is receiving concurrently other treatment modalities against the nasopharyngeal cancer. The subject can be a nasopharyngeal cancer patient who had undergone a regimen of treatment (e.g., chemotherapy and/or radiation) and whose cancer is regressing. The subject may be a nasopharyngeal cancer patient who had undergone a regimen of treatment (e.g., surgery) and who appears to be clinically free of the nasopharyngeal cancer. The biological composition of the invention can be administered adjunctively with any of the treatment modalities, such as but not limited to chemotherapy, radiation, and/or surgery. For example, the biological composition can be used in combination with one or more chemotherapeutic or immunotherapeutic agents, such as cyclosporin A, Taxol, Cisplatin, Carboplatin, Adriamycin, Doxil, Topotecan, Methotrexate, Bleomycin and Epirubicin. The biological composition can also be used after other regimen(s) of treatment is concluded.

The subject may be one who has not yet been diagnosed with nasopharyngeal cancer but are predisposed to or at high risk of developing nasopharyngeal cancer as a result of genetic factors and/or environmental factors. The subject may also be one who displays characteristics that are associated with a high risk of nasopharyngeal cancer, such as nodules detected by computer tomographic scanning or suspect cells in biopsy and/or body fluids.

Depending on the subject, the therapeutic and healthful benefits range from inhibiting or retarding the growth of the nasopharyngeal cancer and/or the spread of the nasopharyngeal cancer to other parts of the body (i.e., metastasis), palliating the symptoms of the cancer, improving the probability of survival of the subject with the cancer, prolonging the life expectancy of the subject, improving the quality of life of the subject, and/or reducing the probability of relapse after a successful course of treatment (e.g., surgery, chemotherapy or radiation). The symptoms associated with nasopharyngeal cancer include neck mass, hearing loss, ipsilateral serous otitis, hearing loss, nasal obstruction, frank epistaxis, purulent or bloody rhinorrhea, and facial neuropathy or facial nerve palsies.

In particular, the invention provides a method for retarding the growth of nasopharyngeal cancer cells in a subject, such as a human, comprising administering orally to the subject a biological composition of the invention. The invention also provide a method for prolonging the time of survival of a subject inflicted with nasopharyngeal cancer, preferably a human patient, comprising administering orally to the subject a biological composition of the invention.

The effective dose will vary with the subject treated. The effective dose for the subject will also vary with the condition to be treated and the severity of the condition to be treated. The dose, and perhaps the dose frequency, will also vary according to the age, body weight, and response of the individual subject. In general, the total daily dose range of activated and conditioned yeast cells for a subject inflicted with nasopharyngeal cancer is from about 10⁵ to 10¹¹ cells per day; preferably, about 10⁸ to 5×10¹⁰ cells per day; more preferably, about 2×10⁹ cells per day in powder form or 9×10⁸ to 1×10¹⁰ cells per day in liquid preparations, administered in single or divided doses orally. The length of time for a course of treatment should be at least 1 week, at least 2 weeks, at least 3 weeks, at least 4 weeks, at least 5 weeks, at least 7 weeks, at least 10 weeks, at least 13 weeks, at least 15 weeks, at least 20 weeks, at least 6 months, or at least 1 year. It may be necessary to use dosages outside these ranges in some cases as will be apparent to those skilled in the art. In certain embodiments, the oral compositions can be administered for a period of time until the symptoms and/or infection of the patients by the bacteria and viruses are under control, or when the disease has regressed partially or completely. For use as a dietary supplement, the total daily dose range should be from about 10⁵ to 10¹¹ cells per day; preferably, about 5×10⁷ to 5×10⁹ cells per day. The oral compositions can be administered as a dietary supplement for as long as 6 months, or in accordance with recommended length of use under the Dietary Supplement Health and Education Act (DSHEA) or other government or industry guidelines. Further, it is noted that the nutritionist, dietician, clinician or treating physician will know how and when to interrupt, adjust, or terminate use of the biological composition as a medicament or dietary supplement in conjunction with individual patient response.

The effect of the biological compositions of the invention on development and progression of nasopharyngeal cancer can be monitored by any methods known to one skilled in the art, including but not limited to measuring: a) changes in the size and morphology of the tumor using imaging techniques such as a computed tomographic (CT) scan or a sonogram; and b) changes in levels of biological markers of risk for nasopharyngeal cancer.

5.2.2 Formulations

The biological compositions of the present invention comprise activated and conditioned live yeast cells prepared as described above in Section 5.1, as active ingredient, and can optionally contain a pharmaceutically acceptable carrier or excipient, and/or other ingredients provided that these ingredients do not kill or inhibit the yeast cells. Other ingredients that can be incorporated into the biological compositions of the present invention, may include, but are not limited to, herbs (including traditional Chinese medicine products), herbal extracts, vitamins, amino acids, metal salts, metal chelates, coloring agents, flavor enhancers, preservatives, and the like.

Any dosage form may be employed for providing the subject with an effective dosage of the oral composition. Dosage forms include tablets, capsules, dispersions, suspensions, solutions, and the like. In one embodiment, compositions of the present invention suitable for oral administration may be presented as discrete units such as capsules, cachets, or tablets, each containing a predetermined amount of activated and conditioned yeast cells, as a powder or granules or as a solution or a suspension in an aqueous liquid, a non-aqueous liquid, an oil-in-water emulsion, or a water-in-oil liquid emulsion. In general, the compositions are prepared by uniformly and intimately admixing the active ingredient with liquid carriers or finely divided solid carriers or both, and then, if necessary, shaping the product into the desired presentation. Such products can be used as pharmaceuticals or dietary supplements, depending on the dosage and circumstances of its use.

The oral compositions of the present invention may additionally include binding agents (e.g., pregelatinized maize starch, polyvinylpyrrolidone or hydroxypropyl methylcellulose); binders or fillers (e.g., lactose, pentosan, microcrystalline cellulose or calcium hydrogen phosphate); lubricants (e.g., magnesium stearate, tale or silica); disintegrants (e.g., potato starch or sodium starch glycolate); or wetting agents (e.g., sodium lauryl sulphate). The tablets or capsules can be coated by methods well known in the art.

Liquid preparations for oral administration can take the form of, for example, solutions, syrups or suspensions, or they can be presented as a dry product for constitution with water or other suitable vehicle before use. The temperature of the liquid used to reconstitute the dried product should be less than 65° C. Such liquid preparations can be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents (e.g., sorbitol syrup, cellulose derivatives or hydrogenated edible fats); emulsifying agents (e.g., lecithin or acacia); non-aqueous vehicles (e.g., almond oil, oily esters, ethyl alcohol or fractionated vegetable oils); and preservatives (e.g., methyl or propyl-p-hydroxybenzoates or sorbic acid). As described below, the preparations can also be made to resemble foods or beverages, containing buffer salts, flavoring, coloring and sweetening agents as appropriate. In certain embodiments, the oral composition is a cell suspension comprising about 10³ to 10¹⁰ cells per ml. The oral composition can be produced by diluting or concentrating the yeast culture medium produced by the method of Section 5.1.5 as required. In less preferred embodiments, the oral composition is a cell suspension containing about 10³ to 10⁶ cells per ml. In more preferred embodiments, the oral composition is a cell suspension containing greater than about 10⁶ to 10¹⁰ cells per ml. In most preferred embodiments, the oral composition is a cell suspension containing about 10⁶ to 5×10⁸ cells per ml. The oral composition can be formulated as a health drink and packaged in liquid containers, each containing a predetermined amount of the liquid yeast culture. Standard methods of quality control and packaging are applied to produce in one embodiment of the invention, oral compositions packaged in liquid containers each comprising about 1 ml, 2 ml, 3 ml, 4 ml, 5 ml, 10 ml, 15 ml, 20 ml, 30 ml, 40 ml, 50 ml, 75 ml, 100 ml, 150 ml, 200 ml, 250 ml, 500 ml, 750 ml, or 1,000 ml of the live yeast cells. The number of container to be taken each day to obtain the total daily dose in a subject depends on the number of activated and conditioned yeast cells contained within each container. For example, a container may comprise 50 ml of liquid with 10⁷ cells per ml and when a total daily dose of about 2×10⁹ cells per day is desired, a subject can drink 4 containers per day to obtain the desired total daily dose.

Generally, because of their ease of administration, tablets and capsules represent the most advantageous oral dosage unit form, in which case solid pharmaceutical carriers as described above are employed. In a preferred embodiment, the composition is a capsule. The capsules can be formulated by any commercially available methods. In certain embodiments, the composition is a capsule containing 5 mg, 10 mg, 15 mg, 20 mg, 25 mg, 30 mg, 40 mg, 50 mg, 75 mg, 100 mg, 150 mg, 200 mg, 300 mg, 400 mg, 500 mg, 600 mg, 700 mg, 800 mg, 900 mg, 1.0 gram, 1.25 gram, 1.5 gram, or 2.0 gram of live yeast cells in powder form. The powder in the capsule comprises about 10⁵ to about 10¹¹ cells per gram; more preferably, about 10⁸ to 5×10¹⁰ cells per gram; and most preferably, about 5×10⁸ cells per gram. The number of capsule to be taken each day to obtain the total daily dose in a subject depends on the number of activated and conditioned yeast cells contained within each capsule. For example, a capsule may comprise about 500 mg of powder with 5×10⁸ cells per gram. To achieve a total daily dose of about 2×10⁹ cells per day, a subject can take two capsules at a time for four times per day.

In another embodiment, the biological compositions comprising activated and conditioned yeast cells can be added directly to foods so that an effective amount of yeast cells is ingested during normal meals. Any methods known to those skilled in the art may be used to add to or incorporate the biological compositions into natural or processed foods, provided that the activated and conditioned yeast cells remain viable. Preferably, the nutritional compositions of the invention are made and stored under conditions, such as temperature, from about 0° C. to 4° C. As used herein, the term “food” broadly refers to any kind of material, liquid or solid, that is used for nourishing an animal, and for sustaining normal or accelerated growth of an animal including humans. Many types of food products or beverages, such as but not limited to, fruit juice, herbal extracts, tea-based beverages, dairy products, soybean product (e.g., tofu), and rice products, can be used to form nutritional compositions comprising the activated and conditioned yeast cells of the invention.

The invention is further defined by reference to the following example describing in detail the animal trials conducted to study the efficacy and safety of activated and conditioned yeast cells of the invention.

6. EXAMPLE

The following example illustrates the benefit of a biological composition of the invention in a rat model of human nasopharyngeal cancer. The growth of the tumor in the rats was studied.

Numerous animal studies have reported the use of Wistar rats in the study of treating nasopharyngeal cancer. The use of orthotopic transplant technique has been highly successful in the development of rat models of human nasopharyngeal cancer.

The biological composition comprising 10⁸ cells per ml of activated and conditioned yeast cells of the strain Saccharomyces carlsbergensis Hansen strain AS2.116 was prepared by the methods described in Section 5.1 and subsections therein.

6.1 Animal Preparation

The animals used to generate the nasopharyngeal cancer cells for the experiments were Wistar rats, male and female, 190 to 210 gram in body weight. The rats were starved for 24 hours before the surgery.

Human nasopharyngeal cancer samples (obtainable from Cancer Institute, The Chinese Academy of Medical Sciences, Beijing, China) were carefully selected before, during, and after surgery in order to ensure engraftment occurred at the original position in the rat. The nasopharyngeal cancer samples were obtained from patients who have not received any radiation, chemotherapy or immune enhancement treatment. Nasopharyngeal cancer samples were divided into sections of about 1 mm³ in size and immediately stored in RPMI-1640 suspension after removal from the human patient.

The animals were generally anaesthetized. The barbiturates was first diluted in saline and then injected at 0.3 to 0.4 ml per animal, or 30 mg per kg body weight into the abdomen of the rats. Under sterile conditions, a 1 cm long opening in the body cavity was cut along the right rib of the rats for engraftment of the tumor. Afterwards, the opening was sutured and the rats were put back into the cage. The animals were allowed to grow for three to five weeks. The animals that showed robust growth of the tumor were used as donors. The tumor was removed from a donor rat and minced aseptically in 4 ml of Hank's solution. The suspension of tumor cells were transplanted into a healthy batch of Wistar rats for experimentation.

6.2 Experimental Design

The rats transplanted with tumor cells were divided into 4 experimental groups of ten rats per group and one control group. The four experimental groups were triplicated (i.e., using a total of 120 rats in the experimental groups). In group AY, the rats received 2.0 ml of the biological composition once per day. In group NY, the rats received 2.0 ml of the untreated yeast cells once per day. In group TSPA, the rats were injected intravenously with 1.5 mg of thiotepa (TSPA) per kg body weight per day. In group CK1, the rats received 2.0 ml of physiological saline once per day. A fifth group of rats, group CK2, which did not receive tumor cells, was given 2.0 ml of physiological saline per day.

The rats received the biological compositions, untreated yeast cells, TSPA or saline on the same day as the tumor cells were transplanted. The rats in group CK2 also started receiving saline on the same day as the other four groups. The biological compositions, untreated yeast cells and saline were administered orally by a feeding tube and the TSPA by intravenous injection for 21 consecutive days. On the 22^(nd) day from tumor inoculation, the rats were sacrificed and the weight of the rats as well as the weight of the tumor were determined by standard techniques.

6.3 Results

Table 4 shows the differences in the weight of the rats and tumors of the rats in the various treatment and control groups.

TABLE 4 mean weight of tumor mean weight of rats and nodules and standard Group standard deviation (g) deviation (mg) AY 214 ± 2.2 0.19 ± 0.21 NY 194 ± 3.2  2.3 ± 0.81 TSPA 207 ± 3.8  1.6 ± 0.74 CK1 197 ± 3.6  2.7 ± 0.84 CK2 215 ± 3.4 not applicable

The rats bearing nasopharyngeal cancer cells that received 2.0 ml of the biological composition of the invention (group AY) showed the least deviation in weight as compared to healthy rats not injected tumor cells (group CK2). The rats in group AY also had less tumor mass as compared to rats that did not receive treatment (group CK1) as well as the rats in group NY (2.0 ml of untreated yeast cells per day) and the rats in group TSPA (1.5 mg of thiotepa per kg body weight per day).

7. EXAMPLE

The following example illustrates the benefit of a biological composition of the invention in a rat model of human nasopharyngeal cancer. The survival time of rats after tumor injection and treatment was studied.

The biological composition comprising 10⁸ cells per ml of activated and conditioned yeast cells of the strain Saccharomyces carlsbergensis Hansen strain AS2.116 was prepared by the methods described in Section 5.1 and subsections therein.

7.1 Animal Preparation

The animals were prepared in a similar manner as described in Section 6.1.

7.2 Experimental Design

The rats transplanted with tumor cells were divided into 4 experimental groups of ten rats per group and one control group. The four experimental groups were triplicated (i.e., using a total of 120 rats in the experimental groups). In group 2AY, the rats received 2.0 ml of the biological composition once per day. In group 2NY, the rats received 2.0 ml of the untreated yeast cells once per day. In group 2TSPA, the rats were injected intravenously 1.5 mg of thiotepa (TSPA) per kg body weight per day. In group 2CK1, the rats received 2.0 ml of physiological saline once per day. A fifth group of rats, group 2CK2, which did not receive tumor cells, was given 2.0 ml of physiological saline per day.

The rats received the biological compositions, untreated yeast cells, TSPA or saline on the same day as the tumor cells were transplanted. The rats in group 2CK2 also started receiving saline on the same day as the other four groups. The biological compositions, untreated yeast cells and saline were administered orally by a feeding tube and the TSPA by intravenous injection for 21 consecutive days. The rats were observed over 6 months from the day of tumor inoculation and survival was recorded. The weight of the rats and the weight of the tumor were determined by standard techniques.

7.3 Results

Table 5 shows the number of rats in the various treatment and control group that survived the tumor injection over a period of 6 months. Each of the 30 rats in each group received 21 consecutive days of either untreated yeast cells, TSPA, saline or biological compositions of the invention. Table 6 shows the weight of the rats that survived and the weight of their tumors in the various treatment and control groups.

TABLE 5 Number of live animals remaining in the groups after 21 days of treatment Time after cessation of Group Group Group Group Group treatment 2AY 2NY 2TSPA 2CK1 2CK2 0 month  30 28 30 30 30 1 month  30 24 26 22 30 2 months 30 5 24 3 30 3 months 30 0 17 0 30 4 months 30 0 7 0 30 5 months 30 0 0 0 30 6 months 30 0 0 0 30

TABLE 6 mean weight of rats mean weight of tumor and standard nodules and standard Group deviation (g) deviation (mg) 2AY 226 ± 8.6 132.5 ± 10.3 2NY all animals dead all animals dead 2TSPA all animals dead all animals dead 2CK1 all animals dead all animals dead 2CK2 229 ± 11.8 not applicable

The rats bearing nasopharyngeal cancer cells that received 2.0 ml of the the tumor never reoccurred. On the contrary, the rats in group 2NY (2.0 ml of untreated yeast cells per day), group 2TSPA (1.5 mg of thiotepa per kg body weight per day) and group 2CK1 (2.0 ml of saline per day) all died after four months from injection of tumor cells.

As in Example 6, the rats bearing nasopharyngeal cancer cells that received 2.0 ml of the biological composition of the invention (group 2AY) showed the least deviation in the weight of rats as compared to healthy rats not injected tumor cells (group 2CK2).

8. EXAMPLE

The following example illustrates the benefit of a biological composition of the invention in a nasopharyngeal cancer mouse model of human nasopharyngeal cancer. The growth of tumors in the mice was studied.

The biological composition comprising 10⁸ cells per ml of activated and conditioned yeast cells of the strain Saccharomyces carlsbergensis Hansen strain AS2.116 was prepared by the methods described in Section 5.1 and subsections therein.

8.1 Animal Preparation

The animals used to generate the nasopharyngeal cancer cells for the experiments were nasopharyngeal cancer mice (obtainable from the Chinese Academy of Military Medical Sciences, Beijing, China), 6 to 8 weeks old, male and female, 18 to 20 gram in body weight. Highly differentiated nasopharyngeal cancer were obtained from the Institute of Medicine, Cancer Laboratory of China. The animals were injected with a suspension containing about 1 viable tumor cells subcutaneously and allowed to grow for 5 days.

8.2 Experimental Design

The mice injected with tumor cells were divided into 4 experimental groups of ten mice per group and one control group. The four experimental groups were triplicated (i.e., using a total of 120 mice in the experimental groups). In group AY, the mice received 0.3 ml of the biological composition once per day. In group NY, the mice received 0.3 ml of the untreated yeast cells once per day. In group CTX, the mice were injected subcutaneously with 30 mg of cyclophosphamide (CTX) per kg body weight per day. In group CK1, the mice received 0.3 ml of physiological saline once per day. A fifth group of mice, group CK2, which did not receive tumor cells, was given 0.3 ml of physiological saline per day.

The mice received the biological compositions, untreated yeast cells CTX or saline on the same day as the tumor cells were transplanted. The mice in group CK2 also started receiving saline on the same day as the other four groups. The biological compositions, untreated yeast cells and saline were administered orally by a feeding tube and the CTX by intravenous injection for 30 consecutive days. On the 31^(st) day from tumor inoculation, the mice were sacrificed and the weight of the mice as well as the weight of the tumor were determined by standard techniques.

8.3 Results

Table 7 shows the differences in the weight of the mice and tumors of the mice in the various treatment and control groups.

TABLE 7 mean weight of tumor mean weight of mice and nodules and standard Group standard deviation (g) deviation (g) AY 20.3 ± 1.7 0.12 ± 0.06 NY 18.5 ± 2.8 0.95 ± 0.23 CTX 19.7 ± 2.4 0.86 ± 0.13 CK1 18.1 ± 2.6 0.98 ± 0.21 CK2 20.6 ± 2.1 not applicable

The mice bearing nasopharyngeal cancer cells that received 0.3 ml of the biological composition of the invention (group AY) showed the least deviation in the weight of mice as compared to healthy mice not injected tumor cells (group CK2). The mice in group AY also had less tumor mass as compared to mice that did not receive treatment (group CK1) as well as the mice in group NY (0.3 ml of untreated yeast cells per day) and the mice in group CTX (30 mg of cyclophosphamide per kg body weight per day).

9. EXAMPLE

The following example illustrates the benefit of a biological composition of the invention in a nasopharyngeal cancer mouse model of human nasopharyngeal cancer. The survival time of mice after tumor injection and treatment was studied.

The biological composition comprising 10⁸ cells per ml of activated and conditioned yeast cells of the strain Saccharomyces carlsbergensis Hansen strain AS2.116 was prepared by the methods described in Section 5.1 and subsections therein.

9.1 Animal Preparation

The animals were prepared in a similar manner as described in Section 8.1.

9.2 Experimental Design

The mice injected with tumor cells were divided into 4 experimental groups of ten mice per group and one control group. The four experimental groups were triplicated (i.e., using a total of 120 mice in the experimental groups). In group 2AY, the mice received 0.3 ml of the biological composition once per day. In group 2NY, the mice received 0.3 ml of the untreated yeast cells once per day. In group 2CTX, the mice were injected intravenously with 30 mg of cyclophosphamide (CTX) per kg body weight per day. In group 2CK1, the mice received 0.3 ml of physiological saline once per day. A fifth group of mice, group 2CK2, which did not receive tumor cells were given 0.3 ml of physiological saline per day.

The mice received the biological compositions, untreated yeast cells, CTX or saline on the same day as the tumor cells were transplanted. The mice in group 2CK2 also started receiving saline on the same day as the other four groups. The biological compositions, untreated yeast cells and saline were administered orally by a feeding tube and the CTX by intravenous injection for 30 consecutive days. The mice were observed over 6 months from the day of tumor inoculation and survival was recorded. The weight of the mice and the weight of the tumor were determined by standard techniques.

9.3 Results

Table 8 shows the number of mice in the various treatment and control group that survived the tumor injection over a period of 6 months. Each of the 30 mice in each group received 30 consecutive days of either untreated yeast cells, CTX, saline or biological compositions of the invention. Table 9 shows the weight of the mice that survived and the weight of their tumors in the various treatment and control groups.

TABLE 8 Number of live animals remaining in the groups after 30 days of treatment Time after cessation of Group Group Group Group Group treatment 2AY 2NY 2CTX 2CK1 2CK2 0 month  30 29 30 27 30 1 month  30 22 27 19 30 2 months 30 7 17 3 30 3 months 30 0 11 0 30 4 months 30 0 3 0 30 5 months 30 0 0 0 30 6 months 30 0 0 0 30

TABLE 9 mean weight of tumor mean weight of mice and nodules and standard Group standard deviation (g) deviation (mg) 2AY 20.3 ± 1.6 178.5 ± 9.3 2NY all animals dead all animals dead 2TSPA all animals dead all animals dead 2CK1 all animals dead all animals dead 2CK2 20.8 ± 1.2 not applicable

The mice bearing nasopharyngeal cancer cells that received 0.3 ml of the biological composition of the invention (group 2AY) survived for more than 6 months and the tumor never reoccurred. On the contrary, the mice in group 2NY (0.3 ml of untreated yeast cells per day), group 2CTX (30 mg of cyclophosphamide per kg body weight per day) and group CK1 (0.3 ml of saline per day) all died during the experiment.

As in Example 8, the mice bearing nasopharyngeal cancer cells that received 0.3 ml of the biological composition of the invention (group 2AY) showed the least deviation in the weight of mice as compared to healthy mice not injected with tumor cells (group 2CK2).

The present invention is not to be limited in scope by the specific embodiments described which are intended as single illustrations of individual aspects of the invention, and functionally equivalent methods and components are within the scope of the invention. Indeed, various modifications of the invention, in addition to those shown and described herein, will become apparent to those skilled in the art from the foregoing description and accompanying drawings. Such modifications are intended to fall within the scope of the appended claims.

All publications, patents and patent applications mentioned in this specification are herein incorporated by reference into the specification to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. 

1. A method of treating yeast cells, comprising at least two steps selected from the group consisting of: a. culturing yeast cells in a first electromagnetic field having a frequency in the range of 9,961 to 9,970 MHz and a field strength in the range of 250 to 270 mV/cm; b. culturing the yeast cells in a second electromagnetic field having a frequency in the range of 10,951 to 10,960 MHz and a field strength in the range of 250 to 270 mV/cm; c. culturing the yeast cells in a third electromagnetic field having a frequency in the range of 12,091 to 12,100 MHz and a field strength in the range of 250 to 270 mV/cm; d. culturing the yeast cells in a fourth electromagnetic field having a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 240 to 270 mV/cm; and e. culturing the yeast cells in a fifth electromagnetic field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 270 to 290 mV/cm, and wherein said method further comprises the step of recovering the cultured yeast cells.
 2. A method of treating yeast cells, comprising at least two steps selected from the group consisting of: a. culturing yeast cells in a first electromagnetic field having a frequency in the range of 9,961 to 9,970 MHz and a field strength in the range of 250 to 270 mV/cm; b. culturing the yeast cells in a second electromagnetic field having a frequency in the range of 10,951 to 10,960 MHz and a field strength in the range of 250 to 270 mV/cm; c. culturing the yeast cells in a third electromagnetic field having a frequency in the range of 12,091 to 12,100 MHz and a field strength in the range of 250 to 270 mV/cm; d. culturing the yeast cells in a fourth electromagnetic field having a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 240 to 270 mV/cm; and e. culturing the yeast cells in a fifth electromagnetic field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 270 to 290 mV/cm, wherein said method further comprising at least one step selected from the group consisting of: f. culturing the yeast cells in a liquid medium comprising wild hawthorn fruit juice and gastric juice of a mammal in a sixth electromagnetic field having a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 260 to 300 mV/cm; and g. culturing the yeast cells in a liquid medium comprising wild hawthorn fruit juice and gastric juice of a mammal in a seventh electromagnetic field having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 290 to 310 mV/cm, and wherein said method further comprises the step of recovering the cultured yeast cells.
 3. The method of claim 2, further comprising before the recovering step the following steps, which can be carried out in any order: h. culturing the yeast cells in a first liquid medium and an eighth electromagnetic field or series of electromagnetic fields having a frequency in the range of 12,441 to 12,450 MHz and a field strength in the range of 215 to 330 mV/cm; and i. culturing the yeast cells in a second liquid medium and a ninth electromagnetic field or series of electromagnetic fields having a frequency in the range of 12,751 to 12,760 MHz and a field strength in the range of 240 to 350 mV/cm, wherein the first and second liquid mediums each comprises wild hawthorn fruit juice, jujube fruit juice, wu wei zi berry juice, and soybean juice.
 4. The method of claim 1, wherein the yeast cells to be treated are cells of Saccharomyces.
 5. The method of claim 1, wherein the yeast cells to be treated are cells of Saceharomyces cerevisiae AS2.1
 16. 6. The method of claim 2 or 3, wherein the yeast cells to be treated are cells of Saccharomyces.
 7. The method of claim 2 or 3, wherein the yeast cells to be treated are cells of Saccharomyces cerevisiae AS2.1
 16. 8. The method of claim 2 or 3, further comprising before the recovering step the following steps: j. drying the yeast cells at a temperature not exceeding 65° C. for a period of time, wherein the yeast cells become dormant; and k. drying the yeast cells at a temperature not exceeding 70° C. for a period of time to reduce the moisture content to below 5%. 